ANNAPOLIS, Md. -- A week after the death of freshman slotback Will McKamey, the Naval Academy football squad resumed spring football drills Tuesday amid questions remaining about what caused the brain trauma that led to his collapse at practice.

"We took time off to mourn," Navy coach Ken Niumatalolo said of the four canceled practices and the team's attendance at McKamey's funeral Monday in Knoxville, Tenn. "There's nothing that prepares you for that."

McKamey, 19, of Knoxville, collapsed during a morning practice March 22 and died three days later after cranial surgery.

The Maryland Office of the Chief Medical Examiner said the cause of death was "traumatic brain injury" from bleeding on the brain and deprivation of oxygen to the brain.

The Navy will investigate the death, as is standard, said Commander John Schofield, the academy's public affairs officer.

"That happens ... whether you are on a ship or at the Naval Academy or at the Pentagon," Schofield said.

Among those at the funeral was running game coordinator and offensive line coach Ashley Ingram, who recruited McKamey.

"He was loved at home, but obviously he was loved here, too. A great loss for all of us," said Ingram, who was on the field when McKamey collapsed. "There was nothing, nothing that happened that you would say, 'Oh, man. There was something there.' There was really nothing obvious that you would have noticed out of the ordinary."

Navy will open its 2014 season against Ohio State on Aug. 30 in Baltimore.

"Like Coach Kenny said, we're going to be mourning for the rest of our lives," said Navy quarterback Keenan Reynolds. "But we've just got to move forward. The only thing we can do is dedicate this season to Will and come out here and work hard and remember him."

Reynolds, also from Tennessee, recalled his first meeting with McKamey and his father Randy, who coached McKamey at Grace Christian Academy in Knoxville.

"I met him when he first came up here last spring to watch us practice," Reynolds said. "I got to know him and his father a little bit. And I can only say good things about that whole family."

McKamey also suffered a brain injury during his senior year of high school but recovered without surgery. His mother, Kara, wrote on Facebook that four neurosurgeons examained her son at the time before clearing him to return to football.

She also wrote that her son "did not sustain a bad hit or unusual or extreme contact" on the day he collapsed at Navy.

"The Navy coaches have poured through the films of practice and seen nothing more than Will carrying the football normally, doing what he truly loves," she wrote.

Asked about that, Niumatalolo said, "It's hard enough that (he) passed away. That's paramount. ... The hard part is we wish we knew what happened."

In the past six weeks, two other Midshipmen have died.

Hans Loewen, 20, of Hampstead, N.C., died Saturday at Baltimore Shock Trauma, a week after sustaining head injuries in a skateboarding accident while away from the academy.

In February, Max Allen, 25, of Chesterfield, Va., was found dead in a submerged vehicle in College Creek on the academy grounds.

"With the three deaths that have taken place here in the last six weeks, we've convened or started a JAGMAN investigation on each one," said Schofield.